Anisotropic Microstructure and Hydrogen Permeability of Nb-Ti-Ni Duplex Phase Alloy Prepared by Hot Forging-Rolling Technique

摘要

Microstructures produced by the forging and the rolling of the Nb_(40)Ti_(30)Ni_(30) alloy at 1173K, and hydrogen permeability (PHI) measured along the different directions of this worked alloy were investigated using a scanning electron microscope (SEM), and a gas flow meter, respectively. The primary (Nb, Ti) phase was elongated along the working direction, and anisotropic microstructures were formed in this alloy. Hydrogen permeability (PHI) measured along the working direction (RD) was 4.4 x 10~(-8) [mol H_2 m~(-1)s~(-1)Pa~(-0.5)] at 673 K, which was 2.5 times higher than that of the as-cast one. On the other hand, the values of PHImeasured along the other directions were lower than this. Thus, PHI of the Nb_(40)Ti_(30)Ni_(30) alloy had a great dependence on the direction of the (Nb, Ti) phase.